In a device of the above-defined type, the action of a key in a rotor or the action of a door knob generates turning movement that needs to be converted into movement in translation of the cremone-bolt rods. Most current systems use locks presenting cylinders that have a so-called “European” profile, also known as “Euro cylinders”. In such a system, a tongue or “bit” is turned by the rotor turning in the cylinder. Generally, that turning movement is free over 270° and then, over 45°, the bit pushes a first piston that unlocks a drive fork for driving the cremone-bolt rods. Finally, over the remaining 45°, the bit drives the fork that is secured to the cremone-bolt rods. The cremone-bolt rods are thus actually driven over only one eighth of a turn of a key, thereby giving rise to an unpleasant sensation of a movement that is jerky and sudden, with successive jolts. In addition, such a short working stroke requires at least two turns of a key in order to engage the lock-bolts of the cremone bolt into the keepers to a sufficient depth lying at least in the range 25 millimeters (mm) to 30 mm.
Above all, for such a Euro cylinder, the outer envelope swept by the turning bit is very wide, so that the cylinder can only be received in a tube that is of inside diameter greater than 32 mm.
Finally, that system is always based on an assembly of parts that are quite fragile and that can be damaged rapidly by abnormal stresses.
The invention makes it possible to overcome all of those drawbacks.